Motion tracking user interface

ABSTRACT

A method to transition focus of a display corresponding to an object&#39;s motion tracked by a video camera or like device is disclosed. In one implementation, the display shows one or more windows or user interfaces on the display. The object&#39;s motion can be used to select one of the windows or user interfaces on the display and manipulate content presented in the window or user interface. In another implementations, the object&#39;s motion can manipulate a three-dimensional graphical icon in a three-dimensional display environment, for example, by rotating it. In another implementation, the method further tracks motion of a second object and shifts focus of the display corresponding to the motion of the second object. In another implementation, a second display may be added to mirror the focus transition corresponding to the object&#39;s motion.

CROSS-REFERENCE TO RELATED APPLICATION

This application is a continuation (and claims the benefit of priorityunder 35 USC 120) of U.S. application Ser. No. 11/956,275, filed Dec.13, 2007, now allowed, and titled “ Motion Tracking User Interface,”which is incorporated by reference.

TECHNICAL FIELD

The subject matter of this patent application generally relates to userinterfaces.

BACKGROUND

Input devices for computer systems commonly include a mouse, a keyboard,or other input devices (e.g., a pen-based device, a track ball, etc).Each of these input devices requires a user's spare hand to operate. Insome cases, a user may need both hands free to complete a task (e.g.,typing on a keyboard) or the user may suffer from a disability thatprecludes the use of one hand. When the user desires to interact withthe computer system, the user must interrupt the task to manipulate aninput device.

SUMMARY

A method to transition focus of a display corresponding to an object'smotion tracked by a video camera or like device is disclosed. In oneimplementation, the display shows one or more windows or user interfaceson the display. The object's motion can be used to select one of thewindows or user interfaces on the display and manipulate contentpresented in the window or user interface. In another implementations,the object's motion can manipulate a three-dimensional graphical icon ina three-dimensional display environment, for example, by rotating it. Inanother implementation, the method further tracks a second object'smotion in the display and shifts focus of the display corresponding tothe motion of the second object. In another implementation, a seconddisplay may be added to mirror the focus transition corresponding to theobject's motion.

Particular embodiments of the subject matter described in thisspecification can be implemented to realize one or more of the followingadvantages. A user can free the use of both hands while navigating auser interface or interacting with an application on a computer system.

DESCRIPTION OF DRAWINGS

FIG. 1 is a screenshot showing a visual tracking of an object, namely, auser's head by a camera or a like device.

FIG. 2 is a screenshot showing visual tracking of an object, a pen,which is manipulated by a user.

FIG. 3 is a screenshot showing a visual tracking of a target zone of auser's head moving from one position to another position.

FIG. 4 is a screenshot showing a pointer indicating focus transitioningof a display among multiple windows concurrently shown on the display.

FIG. 5 is a screenshot showing a three-dimensional graphical icon,namely, a teapot, which is being manipulated by a user using his headmotion.

FIG. 6 is a screenshot showing the icon being moved and manipulated atthe same time by a user using his head motion.

FIG. 7 is a screenshot showing optical flow of a user motion turning hishead from left to right.

FIG. 8 is a flow diagram of an example process for transitioning focusof a display corresponding to an object's motion.

FIG. 9 is a flow diagram of an example process for transitioning agraphical icon's visual presentation corresponding to an object'smotion.

FIG. 10 is a flow diagram of an example process for tracking twoobjects' motions and transitioning focus of display corresponding to thetwo objects' motions.

FIG. 11 is a flow diagram of an example process for tracking an object'smotion and transitioning focus of a second display corresponding to theobject's motion.

FIG. 12 is a block diagram of an example system architecture that can beutilized to implement the systems and methods described in thisapplication.

FIG. 13A-13C are screenshots showing a three-dimensional graphical icon(e.g., a teapot) being displayed from different angles depending on auser's perspectives.

FIG. 14A-14B illustrates changing of views from a user's perspective ina three-dimensional space.

FIG. 15 is a flow diagram of an example process for transitioning agraphical icon's visual presentation concurrently with its visuallocation corresponding to an object's motion.

DETAILED DESCRIPTION Selection of a Target-Zone

FIG. 1 is a screenshot showing a visual tracking of an object, namely, ahead 102 of a user 108 by a video camera or a like device. In theexample shown, a user 108 is in front of the video camera or the likedevice (e.g., Apple Inc.'s iSight® camera). An image 104 of the user'shead 102 is captured by the video camera or the like device anddisplayed on the top right corner of a display 100 (e.g., a computermonitor). The image 104 conveys a message to the user 108 about whichregion of his head 102 is to be tracked by the video camera.

In some implementations, the user 108 can select a target zone to betraced by clicking on a zone of the image 104. In the example shown, theuser 108 has selected the target zone 106 to be his head 102. The videocamera puts the target zone 106 in focus and tracks the motion of thetarget zone 106 relative to the video camera.

In some implementations, the object to be tracked is not necessarily ahuman head. Any tangible objects can be tracked, such as a pen, a box, ahand, etc.

FIG. 2 is a screenshot showing the visual tracking of a pen 202 by thevideo camera. A user 204 is holding the pen 202 in front of a videocamera. An image 206 of the pen 202 captured by the video camera isdisplayed on the top right corner of the screen 200, for example.Similar to FIG. 1, the image 206 conveys a message to the user 204 aboutwhich region of the pen 202 is to be tracked by the video camera. As canbe seen in the image 206, the region targeted is the top of the pen 202.The video camera will accordingly track the top of the pen 202.

In some implementations, selecting a target zone to be tracked byphysical clicking is not necessary. For example, optical flowinformation can be used to automatically detect a moving object withoutadditional effort by a user to select a target zone to be tracked.

Optical flow is a known technology often used in the motion pictureindustry. For each pixel in a frame, a motion vector is calculated whichdescribes a sub pixel x and y movement. A measure of how good a motionvector is, or how different a next frame is, can also be computed. Forexample, an absolute difference can be computed between a pixel in afirst frame shifted by its motion vector and a corresponding pixel in asecond frame. There can also be a confidence level or a penalty computedfor describing how different the pixel is from neighboring vectors.Optical flow can be performed in floating point and often can be storedin OpenEXR file formats.

Target Tracking

FIG. 3 is a screenshot showing tracking of a target zone 302 of a head304 of a user moving from one position to another position. In FIG. 3,the target zone 302 of the user is moving his head 304 from a leftposition to a right position. At the same time, the video camera istracking and, optionally, recording the motion of the target zone 302,such that the tracking information can be used for any of a number ofpurposes (e.g., transitioning focus of a display 300 corresponding tothe motion of the target zone 302).

Focus Transition of a Display

FIG. 4 is a screenshot showing using a pointer 402 to indicate focustransitioning of a display 400 among multiple windows 404 a-404 e. Inthe example shown, windows 404 a, 404 b, 404 c, 404 d, and 404 e areconcurrently shown on the display 400, and each window is displayingcontent (e.g., a digital image).

The pointer 402 is used to indicate the current focus of the display(e.g., the window currently active). More specifically, the pointer 402is used to indicate the transition of focus of the display 400 incorrespondence with the motion of the human head or other object. Forexample, when the human head moves from left to right, the pointer 402shown on the display 400 originally pausing at the window 404 a, shiftsfrom the window 404 a to 404 d in response to the motion, to indicatethat the focus of the display (e.g., the currently active window) hasbeen transitioned from the window 404 a to 404 d. Similarly, if thehuman head or other object move from right to left, the pointer 402shifts from 404 d to 404 c. This way the human head being tracked iscapable of arbitrarily changing the focus of the display 400 from afirst window to a second window, as well as changing the position of thepointer on the display 400.

FIG. 4 illustrates an example of transitioning focus among five windows404 a, 404 b, 404 c, 404 d, and 404 e, which might or might not overlapwith each other on the display 400. The method disclosed in thisapplication can detect the movement of the human head or other objects,and in turn place the pointer on the window intended by the user to befocused on. For example, starting from a point in the window 404 d, ifthe human head moves from upper left to lower right, the pointer willmove correspondingly from upper left to lower right and then bring thewindow 404 e to focus. When the window 404 e is in focus, the window 404e will be automatically raised to the top of all the windows such thatthe user can clearly see the current focus of the display.

In some implementations, after the user selects one of the multiplewindows shown on the display, the user can start to hover the pointerwithin the selected window by slowly moving his head over relativelyshort distances. For example, say the pointer 402 is now placed at thewindow 404 a and the user would like to hover the pointer within thewindow 404 a. He could just slowly move his head over short distances,and the pointer will hover within the window 404 a corresponding to hishead motion. Other patterns of motion can be used to signal a hover. Forexample the motion can be described in terms of a path. The path candefine a pattern, which can be mapped to an appropriate action.

In some implementations, there might be only one window shown on thedisplay at one time. Similar to controlling the pointer to hover withinone of the multiple windows, the user can move his head to shift focuswithin the single window.

In some implementations, the one or more windows (or applications userinterfaces) shown on a display include an editor or a browser. A usercan scroll a digital file presented by the editor or the browser indifferent directions such as up, down, left, and right simply by movinghis head or the other object. For example, say there is a five-page filepresented by a word processor on a display, and only the first page isshown within the workspace of the word processor. If the user would liketo see the last page of the file, he could simply move his head down toscroll the digital file down to the last page. Optionally, he could flipthe digital file page-by-page by slightly moving his head down over arelatively short distance.

In some implementations, the one or more windows (or application userinterfaces) shown on the display present digital images or includethree-dimensional effects (e.g., three-dimensional icons). In someimplementations, the pointer indicating focus of the display can be acursor. In certain computer operating systems, it is advantageous to usemultiple types of cursors.

Manipulation of a Graphical Icon

FIG. 5 is a screenshot showing a three-dimensional graphical icon 502(e.g., a teapot), being manipulated by a user 506 moving his head 508.The pointer 504 indicates the current focus of the display 500. The icon502 as well as the pointer 504 are controlled by the head motion of theuser 506. As described earlier, when the user 506 moves his head 508 ina direction, the pointer 504 will move on the display in response to thehead motion. Likewise, the graphical icon 502 will move along with thepointer 504 in response to the head motion.

In some implementations, the user 506 can manipulate the icon 502linearly (e.g., follow a straight motion path on the display 400) and/ornon-linearly (e.g., follow a curved motion path on the display 400). Forexample, the user 506 can turn his head 508 to the right to make theteapot 502 turn to the right, or turn his head to the left to make theteapot 502 turn to the left. Thus, in a three-dimensional displayenvironment, the head or object motion being tracked by the video cameraor like device, can cause a graphical object to move in six degrees offreedom, including up, down, left, right, backward, forward, rotations,etc.

In some implementations, the graphical icon 502 can serve as an avatarrepresenting a user. A user could control eye positions of an avatarthrough head motions. For example, when the user looks right, his headmotion will trigger the avatar to look right. When the user looks left,his head motion will trigger the avatar look left. In otherimplementations, the avatar could simulate movements that the usermakes, other than rotating or linear moving.

The avatar representation can be broadly applied in computer technology,whether in the form of a three-dimensional model used in computer games,a two-dimensional icon (picture) used on Internet forums or chattingwebsites.

Manipulation of the Graphical Icon and Focus Transition of the Display

FIG. 6 is a screenshot showing a graphical icon 602 (e.g., a teapot),being moved and manipulated at the same time by the user 604 moving hishead 606. In the example shown, two windows 608 a and 608 b areconcurrently shown on a display 600. The icon 602 indicates the currentfocus of the display 600 and follows the user's head motion. The arrow610 in the window 608 b shows the moving direction of the teapot 602.

As shown in FIG. 6, the user 604 is moving the teapot 602 by moving hishead in a linear path from right to left. At the same time, the user 604is arbitrarily manipulating the teapot, like rotating itcounterclockwise. This way the user 604 can switch the current focus ofthe display 600 between the two windows 608 a and 608 b, as well asmanipulate the teapot 602 at the same time. In some implementations,there are more than two windows concurrently shown on the display 600.

Extraction of Optical Flow Information

FIG. 7 is a screenshot showing optical flow of the user 702 when turninghis head 704 from left to right. Optical flow as used in thisapplication is a visual representation approximating a motion of anobject and would likely not be visible to the user in an actualapplication. As can be seen in FIG. 7, lines 706 (e.g., motion vectors)on the left side of the display 700 represent optical flow from left toright simulating the motion of the user 702 turning his head from leftto right. In contrast, dots 708 on the right side of the display 700appear relatively still because there is no object moving in thecorresponding area (e.g., the motion vector has zero components).

In some implementations, it can be advantageous to extract optical flowinformation of an object motion from a background. The optical flowprovides information on direction, intensity, and number of moving partswhich can be captured in real-time by the video camera. Subsequently,the optical flow information can be used for transitioning the currentfocus of a display corresponding to the object motion.

Example Process of Display for Visual Motion-Tracking

FIG. 8 is a flow diagram of an example of transitioning a current focusof a display corresponding to an object's motion tracked by a videocamera or like device. Some implementations of this process have alreadybeen described in reference to FIGS. 1-7.

The process includes visually tracking an object's motion 800 from afirst position to a second position. In some implementations, visuallytracking an object's motion includes using a video camera or a likedevice. The object to be tracked can be any tangible articles, such as ahuman head, a pen, etc.

Responsive to tracking the object's motion, the display transitions itscurrent focus from a first visual presentation (e.g., a first window oruser interface) to a second visual presentation (e.g., a second windowor user interface) corresponding to the object's motion 810. Thetransitioning of focus on the display can be indicated by a pointer or agraphical icon shown on the display.

In some implementations, there are one or more windows shown on thedisplay. The pointer or the graphical icon can hover to signaltransitioning of focus within a window or among multiple windows. If thepointer or the graphical icon is within one window, it can alsomanipulate a digital file presented by the window, by scrolling the fileup, down, left and right, for example.

Example Process of Display for Visual Transition Tracking

FIG. 9 is a flow diagram of an example process for indicating focus of adisplay and transitioning a graphical icon's visual presentationcorresponding to an object's motion. Some implementations of thisprocess are described in reference to FIGS. 5-7.

The process includes indicating a current focus of a display by agraphical icon 900. The focus indication can be facilitated by a pointerin the center of the graphical icon, or simply by the position of thegraphical icon.

The process further includes visually tracking an object's motion from afirst visual state to a second visual state 910. For instance, thecamera tracks a non-linear motion of a user's head, such as rotatingabout an axis clockwise.

Responsive to tracking the object's motion from a first visual state toa second visual state, the process transitions the graphical icon on thedisplay from a first visual presentation to a second visual presentationcorresponding to the object's motion 920. Following the previous exampleillustrated the preceding paragraph, the graphical icon shown on thedisplay will rotate clockwise, corresponding to the clockwise rotatingof the user's head.

In some implementations, the graphical icon indicates a changing of thefocus of a display and rotates itself at the same time while the objectbeing tracked moves both linearly and/or non-linearly. In someimplementations, the graphical icon's motion is not constrained torotating.

Example Process of Display for Multiple Objects

FIG. 10 is a flow diagram of an example process for tracking twoobjects' motions and transitioning focus of display corresponding to thetwo objects' motions. Some steps of this process have been described inreference to FIG. 8.

The process includes visually tracking an object's motion from a firstposition to a second position 1000. After tracking the object's motion,the process transitions focus of a display from a first visualpresentation to a second presentation 1010. The process repeats itselfby visually tracking a second object's motion from a third position to afourth position 1020. Then the process transitions focus of the displayfrom a third visual presentation to a fourth presentation 1030.

The process can be further explained by an example where two or morepeople are sharing and observing a single desktop. Each of them is ableto transition the focus of the desktop by simply moving his or her head.

In some implementations, the two objects being visually tracked can taketurns to move as well as manipulate a graphical icon shown on thedisplay. In an example where the graphical icon is a volleyball, twopeople can take turns to move and spin the volleyball by simply movingtheir heads.

Example Process of Multiple Displays

FIG. 11 is a flow diagram of an example process for tracking an objectmotion and transitioning focus of display corresponding to the objectmotion on a second display.

The process includes visually tracking an object's motion from a firstposition to a second position 1100. Responsive to tracking the object'smotion, the process transitions focus of a display from a first visualpresentation to a second visual presentation corresponding to theobject's motion 1110. The process also transitions focus of a seconddisplay from a third visual presentation to a fourth presentationcorresponding to the object's motion 1120.

In some implementations, the multiple displays are connected bynetworks. Two or more users can, on their respective displays, observeand control focus of a single desktop, or that of a presentation of ashared digital file. By way of illustration, when two or more users chatonline and discuss a file presented on their respective displays, eachof them can transition focus of the presentation of the file by movinghis or her head. As another example, when two or more users play gamesonline, each of them can manipulate a graphical icon (e.g., a volleyballor a basketball), simply by moving his or her head.

System Architecture

FIG. 12 is a block diagram of an example system architecture 1200 thatcan be utilized to implement the systems and methods described inreference to FIGS. 1-11. The system 1200 can, for example, beimplemented in a computer device, such as any one of the personalcomputer devices available from Apple Inc. (Cupertino, Calif., USA), orother personal computer devices. Other example implementations can alsoinclude video processing devices, multimedia processing devices,portable computing devices, etc.

The example system 1200 includes a processing device 1202, a first datastore 1204, a second data store 1206, a graphics device 1208, inputdevices 1210, output devices 612, and a network device 614. A bus system1216, such as a data bus and a motherboard, can be used to establish andcontrol data communication between the components 1202, 1204, 1206,1208, 1210, 1212 and 1214. Other example system architectures, however,can also be used.

The processing device 1202 can, for example, include one or moremicroprocessors having one or more processing cores. The first datastore 1204 can, for example, include a random access memory storagedevice, such as a dynamic random access memory, or other types ofcomputer-readable medium memory devices. The second data store 1206 can,for example, include one or more hard drives, a flash memory, and/or aread only memory, or other types of computer-readable medium memorydevices.

The graphics device 1208 can, for example, include a video card, agraphics accelerator card, a graphics processing unit (GPU) or a displayadapter, and is configured to generate and output images to a displaydevice. In one implementation, the graphics device 1208 can be realizedin a dedicated hardware card connected to the bus system 1216. Inanother implementation, the graphics device 1208 can be realized in agraphics controller integrated into a chipset of the bus system 1216.

Example input devices 1210 can include a video camera, a keyboard, amouse, a stylus, etc., and example output devices 1212 can include adisplay device, an audio device, etc.

The network interface 1214 can, for example, include a wired or wirelessnetwork device operable to communicate data to and from a network 1218.The network 1218 can include one or more local area networks (LANs) or awide area network (WAN), such as the Internet.

In an implementation, the system 1200 includes instructions defining anoperating system stored in the first data store 1204 and/or the seconddata store 1206. Example operating systems can include the MAC OS® Xseries operating system, the WINDOWS® based operating system, or otheroperating systems. Upon execution of the operating system instructions,access to various system objects is enabled. Example system objectsinclude data files, applications, functions, windows, etc. To facilitatean intuitive user experience, the system 1200 includes a graphical userinterface that provides the user access to the various system objectsand conveys information about the system 1200 to the user in anintuitive manner.

This written description sets forth the best mode of the invention andprovides examples to describe the invention and to enable a person ofordinary skill in the art to make and use the invention. This writtendescription does not limit the invention to the precise terms set forth.Thus, while the invention has been described in detail with reference tothe examples set forth above, those of ordinary skill in the art mayeffect alterations, modifications and variations to the examples withoutdeparting from the scope of the invention.

View Changing of a Three-Dimensional Graphical Icon

FIG. 13A-13C are screenshots showing a three-dimensional graphical icon1302 a-1302 c (e.g., a teapot) being displayed from different anglesdepending on a user's perspectives. In the examples shown, a position ofthe user's head or other object, is represented by an indicator 1304a-1304 c on a display 1300 a-1300 c. Note FIG. 13A-13C merely serve asexamples to illustrate how a three-dimensional graphical icon can beviewed on a display from various angles in response to the motion of theuser's head or other object. In some implementations, the indicator 1304a-1304 c is not actually displayed.

In FIG. 13A, the position of the user's head, for example, isrepresented by the indicator 1304 a. In the example shown, the user islooking at the icon 1302 a from a left of the icon 1302 a, after movingthe user's head to the left, relative to the position of the icon 1302 ashown on the display 1300 a. In response to the user's head motion, theicon 1302 a is presented on the display 1300 a in a way as if the icon1302 a is actually viewed by the user from a left angle.

In FIG. 13B, the position of the user's head is represented by theindicator 1304 b. In the example shown, the user is looking at the icon1302 b from a center front of the icon 1302 b shown on the display 1300b, after moving the user's head to the center front, relative to theposition of the icon 1302 b. In response to the user's head motion, theicon 1302 b is presented on the display 1300 b in a way as if the icon1302 b is actually viewed by the user from a center front angle.

In FIG. 13C, the position of the user's head is represented by theindicator 1304 c. In the example shown, the user is looking at the icon1302 c from a top right of the icon 1302 c, after moving the user's headto the top right, relative to the position of the icon 1302 c shown onthe display 1300 c. In response to the user's head motion, the icon 1302c is presented on the display 1300 c in a way as if the icon 1302 c isactually viewed by the user from a top right angle.

In some implementations, the three-dimensional graphical icon 1302a-1302 c is presented to appear closer or farer to the user depending ona distance from the user to the icon 1302 a-1302 c shown on the display1300 a-1300 c. In various implementations, the appearance of the icon1302 a-1302 c shown on the display 1300 a-1300 c is adjusted accordingto both the distance and the angle of the user.

The technology of displaying the three-dimensional graphical icon 1302a-1302 c from different angles and/or in various distances,corresponding to the motion of the user's head or other object, can bebroadly employed in computer graphics, including two-dimensionalgraphics, three-dimensional graphics, and image processing. By way ofillustration, in the field of three-dimensional modeling (a process ofdeveloping a representation of a three-dimensional object viaspecialized software), the user can easily see the object being modeledon the display from different angles and/or in various distances bymoving the user's head or other object.

Changing of Views in a Three-Dimensional Universe

FIG. 14A-14B illustrates changing of views from a user's perspective ina three-dimensional space 1402. In FIG. 14A, a box-shaped space shown ona display 1400 a represents a three-dimensional space 1402. A display1400 a-1400 b correspondingly presents different aspects of thethree-dimensional space 1402 in response to user's head motion.

For purposes of illustration, an axis 1410 a-1410 b in FIG. 14A-14Brepresents a motion path of the user's head. For example, when theuser's head turns right by 60° from a initial point 0°, an index 1412a-1412 b correspondingly points at 60° on the right end of the axis 1410a-1410 b. In various implementations, the axis 1410 a-1410 b and/or theindex 1412 a-1412 b is not actually displayed.

In FIG. 14A, the user initially looks to the front facing the display1400 a, as the index 1412 a indicates. Correspondingly, a side A 1406 ofthe space 1402 is presented on the display to the user, to simulate whatthe user sees as if the user is actually situated in the space 1402.

Following the example illustrated in FIG. 14A, the user in FIG. 14B turnhis head to the right by 30°, as the index 1412 b indicates on the axis1410 b. Imagine the user is situated in the three-dimensional space1402. After the user turns his head to the right by 30°, the user issupposed to face a side B 1408 b of the space 1402. To simulate theuser's view as a result of the head motion, the display 1400 bcorrespondingly presents the side B 1408 b of the space 1402 to theuser.

In some implementations, the aspects of the three-dimensional space 1402look closer or farer depending on the user's distance to the aspectsshown on the display 1400 a-1400 b. In various implementations, theappearance of the aspects of the space 1402 is adjusted according toboth the angle and the distance of the user.

The technology of showing different aspects of the three-dimensionalspace 1402, in response to the motion of the user's head or otherobject, can be broadly employed in video games implemented on variousplatforms. By way of illustration, in a three-dimensional computer gamethat correspondingly presents aspects of a three-dimensional universereflecting the user's viewpoints, the user can conveniently change viewsby motion of the user's head or other object.

Example Process of Display for Tracking of Visual Change in States andLocations

FIG. 15 is a flow diagram of an example process for transitioning agraphical icon's visual presentation concurrently with its visuallocation corresponding to an object's motion. Some implementations ofthe process are described in reference to FIG. 7-9.

The process includes visually determining a current state and a currentlocation of an object 1500. In some implementations, visuallydetermining the object's current state and location involves using avideo camera or a like device.

After determining the object's current state and location, the processvisually tracks motion of the object from a first location (e.g., theobject on the left of the display) and a first visual state (e.g., theobject facing the display) to a second location (e.g., the object on theright of the display) and a second visual state (e.g., the objectturning to the right by 30°) 1510. Responsive to tracking the object'smotion, the display transitions a graphical icon on a display from afirst visual position (e.g., a first window or user interface) and afirst visual presentation (e.g., the graphical icon facing front) to asecond visual position (e.g., a second window or user interface) and asecond visual presentation (e.g., the graphical icon turning to theright by 30°) corresponding to the object's motion 1520.

1-18. (canceled)
 19. A method comprising: tracking motion of an objectwithin a space from a first position within the space to a secondposition within the space; and while tracking the object's motion withinthe space, transitioning the visual presentation of a graphical objecton a display from a first visual presentation on the display to a secondvisual presentation on the display that is different than the firstvisual presentation on the display, wherein: the transitioning comprisesmoving the graphical object within a three-dimensional displayenvironment represented on the display; the moving at least partiallycorresponds to at least a portion of the object's tracked motion; andthe at least a portion of the object's tracked motion comprises rotationof the object about an axis within the space.
 20. The method of claim19, wherein the space is outside of the display.
 21. The method of claim19, wherein the tracking comprises visually tracking the motion of theobject within the space from the first position within the space to thesecond position within the space.
 22. The method of claim 21, furthercomprising using a camera to visually track the motion of the objectwithin the space from the first position within the space to the secondposition within the space.
 23. The method of claim 19, furthercomprising, prior to the tracking, registering a focus on the display toa first portion of the graphical object on the display according to thefirst position of the object within the space, wherein the first visualpresentation on the display comprises the focus registered on the firstportion of the graphical object.
 24. The method of claim 19, furthercomprising, prior to the tracking, receiving a selection of a targetzone of an image of the object to be tracked, wherein the trackingcomprises tracking the motion of the target zone of the object from thefirst position within the space to the second position within the space.25. The method of claim 19, wherein the moving comprises rotating thegraphical object within the three-dimensional display environmentrepresented on the display.
 26. The method of claim 19, wherein: a firstportion of the moving corresponds to a first portion of the object'stracked motion; the axis within the space comprises a first axis withinthe space; the first portion of the object's tracked motion comprisesthe rotation of the object about the first axis within the space; asecond portion of the moving corresponds to a second portion of theobject's tracked motion; and the second portion of the object's trackedmotion comprises movement of the object along a second axis within thespace.
 27. The method of claim 26, wherein the first axis is differentthan the second axis.
 28. The method of claim 19, wherein: a firstportion of the moving corresponds to a first portion of the object'stracked motion; the axis within the space comprises a first axis withinthe space; the first portion of the object's tracked motion comprisesthe rotation of the object about the first axis within the space; thefirst portion of the moving comprises rotating the graphical objectwithin the three-dimensional display environment represented on thedisplay; a second portion of the moving corresponds to a second portionof the object's tracked motion; and the second portion of the object'stracked motion comprises movement of the object along a second axiswithin the space.
 29. The method of claim 28, wherein the second portionof the moving comprises varying the size of the graphical object withinthe three-dimensional display environment represented on the display.30. The method of claim 29, wherein the second axis intersects thedisplay.
 31. The method of claim 30, wherein the second axis isdifferent than the first axis.
 32. The method of claim 19, furthercomprising: tracking motion of another object within the space from athird position within the space to a fourth position within the space;and while tracking the other object's motion within the space,transitioning the visual presentation of the graphical object on thedisplay from the second visual presentation on the display to a thirdvisual presentation on the display that is different than the secondvisual presentation on the display, wherein the transitioning the visualpresentation of the graphical object on the display from the secondvisual presentation on the display to the third visual presentation onthe display corresponds to the other object's tracked motion.
 33. Amethod comprising: displaying a graphical icon on a display in a firstvisual presentation of the graphical icon when an object is in a firstsituation within a space outside the display; detecting non-linearmotion of the object from the first situation within the space to asecond situation within the space; and adjusting the graphical icondisplayed on the display from the first visual presentation to a secondvisual presentation in real-time corresponding to the detectednon-linear motion of the object.
 34. The method of claim 33, wherein theadjusting comprises rotating the graphical icon in a three-dimensionalspace represented in the display from the first visual presentation tothe second visual presentation when the detected non-linear motion ofthe object comprises rotation of the object about an axis within thespace outside the display from the first situation to the secondsituation.
 35. The method of claim 34, wherein the adjusting furthercomprises moving the graphical icon along the three-dimensional spacerepresented in the display from the first visual presentation to thesecond visual presentation when the detected non-linear motion of theobject further comprises movement of the object along another axiswithin the space outside the display from the first situation to thesecond situation.
 36. The method of claim 33, wherein the adjustingcomprises rotating the graphical icon in a three-dimensional spacerepresented in the display from the first visual presentation to thesecond visual presentation when the detected non-linear motion of theobject comprises rotation of the object about an axis within the spaceoutside the display from the first situation to the second situation.37. A non-transitory computer-readable medium operable for storinginstructions, which, when executed by a processor, causes the processorto perform operations comprising: presenting information to a user in afirst presentation of the information when an object is in a firstsituation within a space; detecting non-linear motion of the object fromthe first situation within the space to a second situation within thespace; and adjusting the presentation of the information to the userfrom the first presentation of the information to a second presentationof the information in a manner corresponding to the detected non-linearmotion of the object from the first situation within the space to thesecond situation within the space.
 38. The non-transitorycomputer-readable medium of claim 37, wherein the object is at least aportion of the user's body.